1. Field of the Invention
The present invention relates to an undercut treating device of a die casting mold and a method for treating the undercut, which can improve working safety and productivity by automating the treatment of the undercut.
2. Description of the Related Prior
In general, a conventional die casting machine includes a sliding block mounted between a fixed die and a movable die to produce a product which has a concave portion such that the cast product cannot be ejected in a direction where a mold closes or opens.
Although such a sliding block has caused the mold to be complicated, because of an advantage that the product can be formed by only one process, the sliding block has been used.
The sliding block is used to prevent the undercut from sticking to the mold and avoid ejection of the cast product. However, the most important element when designing the mold is to avoid the trouble with the mold.
Particularly, to cast a transmission case for a vehicle, the die cast mold having an undercut treating means should be used.
FIG. 3 is a side sectional view of a conventional die casting mold. The die casting mold comprises a movable holder 4 supported on a die base 2, a movable die 6 seated on the movable holder 4, and a fixed die 10 mounted on a fixed holder 8 in opposition to the movable die.
A sliding core 12 is located between the movable die 6 and the fixed die 10 and fixed to a sliding holder 14, which operates frontward and rearward, to slide therewith.
In this mold, cavities are formed between the movable and fixed dies 6 and 10 and the sliding core 12. That is, as shown in FIG. 3, a channel is defined on the sliding core 12 to form an undercut and a loose piece 16 is inserted into the sliding core 12. A product is cast into cavities C in a state that the loose piece is inserted into the sliding core 12.
However, the cast product which is cast by the above die casting mold should be separated from the loose piece 16 and, after one cycle of the casting is completed, the loose piece 16 should be inserted again to the mold.
Accordingly, work for inserting the loose piece to the mold and for separating the loose piece from the cast product is required such that productivity and working safety are deteriorated.